The present invention generally relates to a control system for a copying machine.
Generally, in a photoelectronic copying machine, a so-called, automatic shutoff mechanism is employed for automatically stopping a main motor for a predetermined period of time after the completion of a series of copying operations. This automatic shutoff mechanism comprises a predetermined automatic timer adapted to be driven subsequent to the completion of post-processes following the copying operation, such as interruption of high voltage electrical power from a power source, and to interrupt the main motor after the lapse of the predetermined period of time.
In this type of copying machine, a jam detecting mechanism including a sensor for monitoring the passage of a copying paper through a predetermined path is also employed for generating a jam signal indicative of the occurrence of the jamming of a copying paper in the path, which jam signal is generated when the copying paper is not in a properly supplied condition at the elapsed time of a predetermined time period after the initiation of the supply of such copying paper.
In view of the recent trend that the control of the copying machine be diversified, the use has been proposed or suggested either of a paper supply failure detecting mechanism for detecting a failure in the supply of the copying paper at a paper supply unit in the copying machine so that, in the event of the occurrence of the paper supply failure, the jam detection to be performed subsequent to the detection of the paper supply failure can be interrupted to effect a control different from that effected when the occurrence of the paper jam would have been detected, or of a function mode enabling the copying machine to continue its copying operation, while the jam detection is interrupted, for the purpose of enabling the machine to be checked during the fabrication thereof at a factory and/or a service man to check the sequence of operation of the copying machine.
In the copying machine of the type wherein the jam detecting operation can be interrupted as hereinabove discussed, there has been found the possibility that, during the execution of the function mode an erroneous operation can take place, for example, in detecting a paper supply failure and the copying paper is left remaining in the transport path at the time of termination of the copier operation with no jam signal being generated. In such a case, the copying paper to be subsequently supplied is likely to result in the occurrence of a paper jam, requiring the operator to remove the copying papers remaining in the path in a jammed condition.
This problem may be removed by using an automatic timer having a relatively long preset time, but the use of such a timer may result in the necessity of the main motor being driven for a prolonged period of time. Accordingly, when one considers the efficiency during the trial run at the factory, the period is desired to be as small as possible.